Avalanche Problems

The 8 avalanche problems used in forecasting. Understanding these helps you interpret forecasts and make better terrain decisions.

What are Avalanche Problems?

Avalanche forecasters organize conditions into these 8 problem types. Each forecast identifies which problems exist, where they're found (elevation/aspect), their likelihood, and expected size. This framework helps you match terrain choices to current conditions.

🌨️

Storm Slab

New snow bonding poorly to the old snow surface or within the new snow itself. Fresh storm snow creates reactive slabs that are sensitive to human triggers.

💨

Wind Slab

Wind-transported snow forming cohesive slabs on lee slopes. Wind creates dense, stiff slabs that bond poorly to the underlying surface.

⏳

Persistent Slab

Slab formed over a persistent weak layer that can remain sensitive for weeks or months. Often surface hoar, facets, or depth hoar.

🎿

Deep Persistent Slab

Slab over a deep persistent weak layer (often depth hoar or facets). Extremely dangerous - rare to trigger but catastrophic when they release.

☀️

Wet Loose Avalanche

Point release of wet snow that entrains more snow as it descends. Caused by water infiltrating and weakening the snowpack.

💧

Wet Slab Avalanche

Cohesive slab of wet snow failing. Water weakens bonds within snowpack creating dangerous slab conditions.

🏔️

Glide Avalanche

Entire snowpack sliding on the ground. Glide cracks indicate movement but release timing is unpredictable.

❄️

Loose Dry Avalanche

Non-cohesive dry snow sluffing. Usually small point releases but can entrain significant amounts of snow on steep terrain.

Using Avalanche Forecasts

1. Check Daily

Read your local forecast every morning, even if not going out. Learn how forecasters describe conditions.

2. Identify Active Problems

Look for which of the 8 problems exist today. Forecasts list them in order of concern.

3. Note Elevation & Aspect

Pay attention to where problems exist. Sometimes different elevations have different problems.

4. Match Terrain to Problems

Avoid terrain where problems exist. Choose slopes that don't match problem parameters.

5. Reassess in Field

Forecasts are regional. Observe actual conditions and adjust plans if observations don't match forecast.